Surface melt and subsequent firn air depletion can ultimately lead to disintegration of Antarctic ice shelves causing grounded glaciers to accelerate and sea level to rise. In the Antarctic Peninsula (AP), foehn winds enhance melting near the grounding line, which in the recent past has led to the disintegration of the most northerly ice shelves. Here, we provide observational and model evidence that this process also occurs over an East Antarctic (EA) ice shelf, where meltwater-induced firn air depletion is found in the grounding zone. Unlike the AP, where foehn events originate from episodic interaction of the circumpolar westerlies with the topography, in coastal EA high temperatures are caused by persistent katabatic winds originating from the ice sheet's interior. Katabatic winds warm and mix the air as it flows downward and cause widespread snow erosion, explaining >3 K higher near-surface temperatures in summer and surface melt doubling in the grounding zone compared to its surroundings. Additionally, these winds expose blue ice and firn with lower surface albedo, further enhancing melt. The in-situ observation of supraglacial flow and englacial storage of meltwater suggests that ice shelf grounding zones in EA, like their AP counterparts, are vulnerable to hydrofracturing.

The DEM is a mosaic of 42 TanDEM-X scenes acquired in 2013. The TanDEM-X SLC data were provided by the German Space Agency (DLR) within the proposal ATI_GLAC0267. The individual DEMs for each SLC scene were processed with the commercial software package SARSCAPE at the Alfred-Wegener-Institute. The final DEM with a pixel resolution of 10 m is provided as GeoTiff (Polarstereographic projection "EPSG:3031", WGS84).Data contact: Veit Helm (mailto:veit.helm@awi.de)

Supplement to: Lenaerts, Jan T M; Lhermitte, Stef; Drews, Reinhard; Ligtenberg, Stefan R M; Berger, Sophie; Helm, Veit; Smeets, Paul; van den Broeke, Michiel R; van de Berg, Willem Jan; van Meijgaard, Erik; Eijkelboom, Mark; Eisen, Olaf; Pattyn, Frank (2016): Meltwater produced by wind-albedo interaction stored in an East Antarctic ice shelf. Nature Climate Change